Computer- Random Shutdowns, what could it be?

[VistaGamer]

For a while now my computer has had random shutdowns. Me and my Friend started trying to figure out what could be causing these problems.

The first thing we tested was the PSU. We thought that the thing might have been faulty (it is a Corsair 650) so I sent that to Corsair to be fixed. When I got it back The computer still had random Shutdowns.

The second thing we tested was the CPU ( AMD Athlon 64x2 6000). I suggested it could have been overheating because either the fan wasn't running well or that the thing was faulty. So we replaced that ( with my old Cpu, AMD Athlon 64x2 4200. I am going to call AMD soon and see if we can fix my newer, obviously better one) and it's somewhat better. The only problem now is that it has faster random shutdowns when I first turn on my computer, then it starts running properly.


What can it be that is causing these problems? I can't find a pattern in the Shutdowns, it happens any time while my computer is on. The screen doesn't go BSOD, it just closes. Could it be the Mobo, maybe?

 

[Hefemeister]

what temps do you have on your cpu and gpu?
If you do not have a monitoring program you can use realtemp, coretemp or speedfan.

 

[H4x3r]

the first thing that pops into my head is overheating like Hefe said, get a monitoring program and post the temps here while idle, and under load. also check the error report to see if something in windows is causing it.